A "mole" is a foot-controlled input device for a computer, particularly one capable of specifying an on-screen position. Circumstances in which a mole can facilitate computer access are when the user: . has a permanent handicap of the upper body, but unimpaired lower body functionality. Such handicaps include amputation, congenital deformity, or paralysis; . has a temporary handicap such as a fracture. Mole facility is acquired with just a little practice; . is performing a technical task requiring both hands, e.g., microscope operation. More generally, a mole may be useful whenever a locational device is required as part of a man/machine interface in industry, medicine, science, and the arts. During Phase II we propose to: . conduct experiments with the current mole prototype to optimize foot switch usage and cursor motion; . drawing upon previous experience, design and implement a new, functionally improved yet more practical generation of mole prototypes; . evaluate features and performance of the new prototypes through experiments with non-handicapped subjects; . adapt certain prototypes to meet specific needs of handicapped individuals; . based upon insights gleaned, design a production prototype; . provide mole interfaces to PS/2s, MacIntoshes, and Suns; . create hardware and software permitting simultaneous use of two positioning devices.